Termites belong to the order of Insects known as isoptera. 
They are social insects that live in large colonies and eat wood. Certain protozoa and bacteria in their Intestines convert the cellulose of the wood into sugars, which provide nourishment.
In the United States there are three main groups of termites:

Drywood Termites, which build their colonies in the dry wood.

Dampwood Termites, which are found In soil and in the wood of buildings. They need not return to the soil if sufficient moisture is present in the structure, such as wood in contact with the ground or constant moisture.

Subterranean Termites, which build their colonies in the soil, from which they have to move to locate the wood on which they feed. Subterranean termites are by far the most common in the Sun Cities Arizona area.  Subterranean termites must live in an atmosphere possessing constant temperature and favorable humidity. To achieve these conditions, they build air-tight tunnels or passages from their nests to their feeding places. The tunnels are made by the workers from wood or soil particles cemented together with saliva and fecal material. A knowledge of these behavioral characteristics of termites Is fundamental to achieving effective control. 

Photo courtesy  Fidelity Exterminating Specialists, Inc.

Differences between flying ants and termites.                                                       

 We are Termidor® Certified 

Wheeler's termites do not cause structural damage to homes. [Pictures]
They construct wide plaster-like earthen tubes on palm trees or wooden structures  where they feed by scraping dead wood off the exterior.

Termite Baits a guide for homeowners:  Research and practical experience with the professionally-installed baits indicates that they require careful installation, diligent monitoring, and ongoing surveillance by a trained individual.  Furthermore, not all termite baiting systems are equally effective. Some products have had difficulty eliminating termite infestations within structures and have required supplemental treatment with other methods.
University of Kentucky: Do it yourself termite baits: Do they work?

For more than you want to know about termites :^)
Visit: United Exterminating's termite page.  A very informative site. 

Links:

Drywood Termite damage
Swarmer of western drywood termite are about 7/16-1/2 inch long the head and pronotum are orange brown, abdomen is dark brown, wing membrane and pigmented veins are blackish. The Soldiers head is orange to reddish brown with a whitish eye spot. The western drywood termite produces usually hard pellets, less than 1/32 inch long, long, oval shaped with rounded ends, 6 concave sides. They are found in the Southwestern U.S., Northwestern Mexico and may also be established in Florida. Western drywood termites infest wood with a moisture content of 12% or less. Drywood termites do not live in the ground, do not build mud tubes, nor require ground contact ground. Colonies are located in the wood they eat, and are smaller than those of subterranean termites. There is no worker caste; immatures and nymphs do the work. After swarming, they find cracks or knotholes in nearby wood, gnaw a small tunnel, close it, excavate a chamber, and mate. The pair may remain dormant for nearly a year, or lay up to 5 eggs, 20 nymphs and 1 soldier. At the end of the 2nd year, the colony may have 6-40 nymphs and 1 soldier; by the 3rd year there may be 40-165 individuals; by the 4th year, 70-700 individuals, at which time the first swarmers may be realized. Swarming of drywood termites, in dozens or occasionally hundreds, typically happens in September/October, at mid-day in warm, sunny weather 80 degrees F, peaking after a sudden temperature increase. In Arizona, drywood termites swarm at night in July. These swarmers are attracted to light. Drywood termites are distributed by human activity, like the shipping of infested furniture, picture frames, and lumber, to new areas. Swarmers drywood termites fly into structures, directly infesting the wood, first in exposed places such as door and window frames, eaves, attics, and molding, or where shingles and paper overhang timber, finding a protected joint or crevice. They often re-infest the same structure when swarming.